Antenna dishes are used by ground devices to communicate with satellite systems. For applications where the ground devices transmit signals to the satellites, these dishes provide narrow, high-gain beams which facilitate signal transmission through the earth's atmosphere.
Such antennas could be used in satellite communication systems using either geosynchronous (GEO) satellites or non-geosynchronous satellites, such as low-earth orbiting (LEO) satellites. LEO satellite orbits move with respect to the surface of the earth. Thus, if communications is to be maintained, an antenna dish which communicates with a LEO satellite would require a gimbal device to enable the dish to track the satellite movement.
A number of non-geosynchronous satellite networks have been proposed which would provide communications services to a large consumer base. In order to be viable in a competitive market, consumer devices which communicate with a non-geosynchronous network should be inexpensive and reliable. For home consumer use, it also is desirable to provide a consumer device which is relatively quiet and compact.
Gimbaled antennas are not an optimal solution for a consumer-based non-geosynchronous satellite system. These antennas typically are large, expensive, noisy, and not extremely reliable. Potentially adding to the expense and complexity of gimbaled antenna solutions is the fact that some non-geosynchronous systems could require make-before-break communication between the consumer device and the satellite network. In such systems, at least two satellite dishes and gimbal systems would be required to maintain communications. Thus, because of the complexity, reliability, and expense of gimbaled antenna systems, they do not provide an optimum solution for satellite-network consumer devices.
Electronically scanned phased array antennas have also been used in applications where a directional beam is desired. Electronic phased array antennas enable signals to be electrically steered without the necessity for mechanical gimbal devices. Unfortunately, electronically scanned array antennas which can be produced from current technology are extremely expensive, which means that such antennas would not be viable in the consumer market.
Because current technologies do not make steerable-beam antennas viable for commercial satellite communications applications, what is needed is a method and apparatus which provides an inexpensive, reliable, quiet, compact antenna to provide ground-to-satellite communication links within a non-geosynchronous satellite system.